Journal ArticleDOI
Full-scale measurements of blade-vortex interaction noise
D. A. Boxwell,F. H. Schmitz +1 more
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This article is published in Journal of The American Helicopter Society.The article was published on 1982-10-01. It has received 54 citations till now. The article focuses on the topics: Vortex & Noise (radio).read more
Citations
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Journal ArticleDOI
On the applicability of background oriented optical tomography for large scale aerodynamic investigations
TL;DR: In this article, the density fields of the blade tip vortices from a helicopter in hover flight were visualized by a technique which does not require any installation on the helicopter or close to it.
Journal ArticleDOI
Helicopter impulsive noise: Theoretical and experimental status
F. H. Schmitz,Y. H. Yu +1 more
TL;DR: The theoretical and experimental status of helicopter impulsive noise is reviewed in this article, where two major sources of helicopter noise are addressed: high-speed impulsive noises and blade- vortex interaction noise.
Journal ArticleDOI
Key Results from a Higher Harmonic Control Aeroacoustic Rotor Test (HART)
W. R. Splettstoesser,Roland Kube,W. Wagner,U. Seelhorst,A. Boutier,F. Micheli,Edzard Mercker,Kurt Pengel +7 more
TL;DR: In this article, the effects of the higher harmonic blade pitch control technique on blade-vortex interaction (BVI) impulsive noise and vibration reduction were investigated with a BO-105 main rotor operated in the open-jetanechoic test section of the German-Dutch wind tunnel.
Journal ArticleDOI
Reduction of helicopter blade-vortex interaction noise by active rotor control technology
Yung H. Yu,Bernd Gmelin,Wolf R. Splettstoesser,Jean Jacques Philippe,Jean Prieur,Thomas F. Brooks +5 more
TL;DR: A review of active rotor control techniques for rotor blade vortex interaction noise reduction, including higher harmonic pitch control, individual blade control, and on-blade control, can be found in this paper.
An experimental investigation of the parallel blade-vortex interaction
TL;DR: In this article, a scheme for investigating the parallel blade vortex interaction (BVI) has been designed and tested, which involves setting a vortex generator upstream of a nonlifting rotor so that the vortex interacts with the blade at the forward azimuth.
References
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Theory of Noise Generation From Moving Bodies With an Application to Helicopter Rotors
TL;DR: Several expressions for the determination of the acoustic field of moving bodies are presented in this paper, based on the Fowcs Williams-Hawkings equation Applying some criteria proposed herin, one of these expressions is singled out for numerical computation of acoustic pressure signature The compactness of sources is not assumed and the main results are not restricted by the observer position.
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A theoretical study of helicopter rotor noise
M.V. Lowson,J. B. Ollerhead +1 more
TL;DR: In this article, a comprehensive theoretical study of the problem of helicopter rotor noise radiation is presented, which includes blade slap, rotation noise and vortex noise effects, including all effects of fluctuating airloads and all possible rigid and flexible blade motions.
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Helicopter Noise due to Blade‐Vortex Interaction
TL;DR: In this article, a theoretical model for the radiated sound due to the transient lift fluctuations is presented, and expressions for the directivity, frequency spectrum, transient signal, and total power of the acoustic signal are derived.
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Theory of open supersonic rotor noise
D L Hawkings,M V Lowson +1 more
TL;DR: In this article, a theory is presented describing the noise generated by open rotors operating at supersonic tip speeds, based upon a combination of the LighthiIl aerodynamic sound theory and the Whitham weak shock theory.
In-Flight Far-Field Measurement of Helicopter Impulsive Noise
TL;DR: In this paper, an in-flight technique for measuring UH-1H helicopter impulsive noise (sometimes called "blade slap") by stationkeeping with a quiet instrumented lead aircraft was found to be highly successful.